Color verification, judging the accuracy of color reproduction, is performed on printed colors when an image forming apparatus prints using a new type of paper. To conduct the color verification, for example, a color image forming apparatus outputs a color chart without color management (including color space conversion), the output color chart is measured by a color measurement instrument, and a printer profile is created by using data of the measured colors. Successively, after color management has been performed by using the created printer profile (alternatively, if the printer profile has been created beforehand, by using the given printer profile), the color image forming apparatus outputs a color chart again, the output color chart is measured by the color measurement instrument, and color verification is made by using data of the measured colors. If a verification result indicating unacceptable color reproduction accuracy is obtained, the color image forming apparatus executes color calibration using its color calibration function, and outputs a color chart again. Then, until a verification result indicating acceptable color reproduction accuracy is obtained, output of a color chart, color measurement, and color calibration are executed repeatedly.